Pin header connectors for two piece connector systems having contact elements with posts for insertion into plated holes in a circuit board such as a back panel are well known in the art. U.S. Pat. No. 4,867,690 discloses one such connector in which the pins are staked into a molded housing with pins extending into an outwardly open cavity and posts extending outwardly from a base surface for insertion into plated through holes of the circuit board. Since this type of header requires the plurality of plated through holes in the circuit board, it is particularly suitable for multi-layer circuit boards. In many instances, however, it is more advantageous to use surface mounted contact terminals to minimize the number of holes in the circuit board particularly in single layer boards. U.S. patent Ser. No. 07/452,523, filed Dec. 18, 1989, and owned by the assignee of the present invention, discloses a pin header having a plurality of contact terminals having contact portions designed to interconnect with circuitry on the surface of a panel. The pin header includes a housing having a plurality of terminal members, each having a C-shaped spring arm with outwardly facing contact surfaces for electrically engaging the circuits of a panel.
The pin header as disclosed in Ser. No. 07/452,523 includes a plurality of inserts disposed in a metal shell, each of the inserts including an array of contact terminals disposed in a dielectric housing, the insert being sized to be frictionally received within corresponding cavities of the shell member. The number of inserts included in a particular connector depends upon the number of interconnections desired between the connector and the panel. In today's electronic industry there is increasing need for higher density connectors, having larger pin counts as well as more closely spaced arrays of terminal members. The higher density connectors are particularly suitable for surface mounting, since this eliminates the need for holes through the circuit board and the space considerations associated therewith. Concomitantly, the size of the circuit pads on the circuit board or panel must be minimized in order to space them more closely together. It is necessary, therefore, to control the manufacturing and assembly processes to prevent misalignment of corresponding terminals and pads owing to an accumulation of tolerance variations. Furthermore, as the number of contact terminals is increased in the connector, the number of inserts may also be increased and the tolerances associated with the addition of further terminal carrying inserts can accumulate such that the surface mounted contact sections of the terminals do not engage the corresponding circuit paths at all locations along the entire length of the connector.
It is desirable therefore, to provide a connector with a plurality of "floatable" modular inserts, each insert having means to align the corresponding terminal contact portions with the circuit pads of the circuit board independently of any other inserts in the connector and independently of the means for mounting the connector to the circuit substrate.